#ifndef __RBTREE_AUGMENTED_H__
#define __RBTREE_AUGMENTED_H__

#include <rbtree.h>

struct rb_augment_callbacks {
	void (*propagate)(struct rb_node *node, struct rb_node *stop);
	void (*copy)(struct rb_node *old, struct rb_node *new);
	void (*rotate)(struct rb_node *old, struct rb_node *new);
};

extern void __rb_insert_augmented(struct rb_node * node, struct rb_root * root,
	int newleft, struct rb_node ** leftmost,
	void (*augment_rotate)(struct rb_node * old, struct rb_node * new));

static inline void rb_insert_augmented(struct rb_node * node, struct rb_root * root, const struct rb_augment_callbacks * augment)
{
	__rb_insert_augmented(node, root, 0, NULL, augment->rotate);
}

static inline void rb_insert_augmented_cached(struct rb_node * node, struct rb_root_cached * root, int newleft, const struct rb_augment_callbacks * augment)
{
	__rb_insert_augmented(node, &root->rb_root, newleft, &root->rb_leftmost, augment->rotate);
}

#define RB_DECLARE_CALLBACKS(rbstatic, rbname, rbstruct, rbfield,	\
			     rbtype, rbaugmented, rbcompute)					\
static inline void													\
rbname ## _propagate(struct rb_node *rb, struct rb_node *stop)		\
{																	\
	while (rb != stop) {											\
		rbstruct *node = rb_entry(rb, rbstruct, rbfield);			\
		rbtype augmented = rbcompute(node);							\
		if (node->rbaugmented == augmented)							\
			break;													\
		node->rbaugmented = augmented;								\
		rb = rb_parent(&node->rbfield);								\
	}																\
}																	\
static inline void													\
rbname ## _copy(struct rb_node *rb_old, struct rb_node *rb_new)		\
{																	\
	rbstruct *old = rb_entry(rb_old, rbstruct, rbfield);			\
	rbstruct *new = rb_entry(rb_new, rbstruct, rbfield);			\
	new->rbaugmented = old->rbaugmented;							\
}																	\
static void															\
rbname ## _rotate(struct rb_node *rb_old, struct rb_node *rb_new)	\
{																	\
	rbstruct *old = rb_entry(rb_old, rbstruct, rbfield);			\
	rbstruct *new = rb_entry(rb_new, rbstruct, rbfield);			\
	new->rbaugmented = old->rbaugmented;							\
	old->rbaugmented = rbcompute(old);								\
}																	\
rbstatic const struct rb_augment_callbacks rbname = {				\
	.propagate = rbname ## _propagate,								\
	.copy = rbname ## _copy,										\
	.rotate = rbname ## _rotate										\
};

#define	RB_RED		0
#define	RB_BLACK	1

#define __rb_parent(pc)		((struct rb_node *)(pc & ~3))
#define __rb_color(pc)		((pc) & 1)
#define __rb_is_black(pc)	__rb_color(pc)
#define __rb_is_red(pc)		(!__rb_color(pc))
#define rb_color(rb)		__rb_color((rb)->__rb_parent_color)
#define rb_is_red(rb)		__rb_is_red((rb)->__rb_parent_color)
#define rb_is_black(rb)		__rb_is_black((rb)->__rb_parent_color)

static inline void rb_set_parent(struct rb_node * rb, struct rb_node * p)
{
	rb->__rb_parent_color = rb_color(rb) | (unsigned long)p;
}

static inline void rb_set_parent_color(struct rb_node * rb, struct rb_node * p, int color)
{
	rb->__rb_parent_color = (unsigned long)p | color;
}

static inline void __rb_change_child(struct rb_node * old, struct rb_node * new,
	struct rb_node * parent, struct rb_root * root)
{
	if (parent) {
		if (parent->rb_left == old)
			parent->rb_left = new;
		else
			parent->rb_right = new;
	} else
		root->rb_node = new;
}

extern void __rb_erase_color(struct rb_node * parent, struct rb_root * root,
	void (*augment_rotate)(struct rb_node * old, struct rb_node * new));

static inline __attribute__((always_inline)) struct rb_node *
__rb_erase_augmented(struct rb_node * node, struct rb_root * root,
		struct rb_node ** leftmost,
		     const struct rb_augment_callbacks *augment)
{
	struct rb_node *child = node->rb_right;
	struct rb_node *tmp = node->rb_left;
	struct rb_node *parent, *rebalance;
	unsigned long pc;

	if (leftmost && node == *leftmost)
		*leftmost = rb_next(node);

	if (!tmp) {
		/*
		 * Case 1: node to erase has no more than 1 child (easy!)
		 *
		 * Note that if there is one child it must be red due to 5)
		 * and node must be black due to 4). We adjust colors locally
		 * so as to bypass __rb_erase_color() later on.
		 */
		pc = node->__rb_parent_color;
		parent = __rb_parent(pc);
		__rb_change_child(node, child, parent, root);
		if (child) {
			child->__rb_parent_color = pc;
			rebalance = NULL;
		} else
			rebalance = __rb_is_black(pc) ? parent : NULL;
		tmp = parent;
	} else if (!child) {
		/* Still case 1, but this time the child is node->rb_left */
		tmp->__rb_parent_color = pc = node->__rb_parent_color;
		parent = __rb_parent(pc);
		__rb_change_child(node, tmp, parent, root);
		rebalance = NULL;
		tmp = parent;
	} else {
		struct rb_node *successor = child, *child2;

		tmp = child->rb_left;
		if (!tmp) {
			/*
			 * Case 2: node's successor is its right child
			 *
			 *    (n)          (s)
			 *    / \          / \
			 *  (x) (s)  ->  (x) (c)
			 *        \
			 *        (c)
			 */
			parent = successor;
			child2 = successor->rb_right;

			augment->copy(node, successor);
		} else {
			/*
			 * Case 3: node's successor is leftmost under
			 * node's right child subtree
			 *
			 *    (n)          (s)
			 *    / \          / \
			 *  (x) (y)  ->  (x) (y)
			 *      /            /
			 *    (p)          (p)
			 *    /            /
			 *  (s)          (c)
			 *    \
			 *    (c)
			 */
			do {
				parent = successor;
				successor = tmp;
				tmp = tmp->rb_left;
			} while (tmp);
			child2 = successor->rb_right;
			parent->rb_left = child2;
			successor->rb_right = child;
			rb_set_parent(child, successor);

			augment->copy(node, successor);
			augment->propagate(parent, successor);
		}

		tmp = node->rb_left;
		successor->rb_left = tmp;
		rb_set_parent(tmp, successor);

		pc = node->__rb_parent_color;
		tmp = __rb_parent(pc);
		__rb_change_child(node, successor, tmp, root);

		if (child2) {
			successor->__rb_parent_color = pc;
			rb_set_parent_color(child2, parent, RB_BLACK);
			rebalance = NULL;
		} else {
			unsigned long pc2 = successor->__rb_parent_color;
			successor->__rb_parent_color = pc;
			rebalance = __rb_is_black(pc2) ? parent : NULL;
		}
		tmp = successor;
	}

	augment->propagate(tmp, NULL);
	return rebalance;
}

static inline __attribute__((always_inline)) void
rb_erase_augmented(struct rb_node * node, struct rb_root * root,
		   const struct rb_augment_callbacks * augment)
{
	struct rb_node * rebalance = __rb_erase_augmented(node, root, NULL, augment);
	if (rebalance)
		__rb_erase_color(rebalance, root, augment->rotate);
}

static inline __attribute__((always_inline)) void
rb_erase_augmented_cached(struct rb_node * node, struct rb_root_cached * root,
			  const struct rb_augment_callbacks * augment)
{
	struct rb_node * rebalance = __rb_erase_augmented(node, &root->rb_root,
							 &root->rb_leftmost,
							 augment);
	if (rebalance)
		__rb_erase_color(rebalance, &root->rb_root, augment->rotate);
}

#endif	/* __RBTREE_AUGMENTED_H__ */
